Software for CAD (computer assisted design) is typically used to design a part, and software for CAM (computer assisted manufacturing) is typically used to make the part. It would be desirable to develop CAS (computer assisted setup) that works together with the CAM process to allow more efficient and more accurate operation of part manufacturing. Ideally, CAS would assist the machinist during setup of the machine tool table and also during the fabrication process.
A CAD process creates an engineering drawing comprising a 3D digital representation of a part. For a square prism type part, the 3D digital representation may contain six views represented by orthographic projections that describe features to be machined into each of the six faces. The CAM process provides all the details necessary for the CNC (computer numeric control) mill to machine this part starting from a solid blank material, called the work piece. The CAM process also gives instructions whereby the machinist may have to place and replace this work piece six or more times. Drawing origin coordinates Xdi, Ydi, and Zdi may be defined; in the case of a square prism i may range from 1 to 6, for each of the six faces of the work piece that is held in a vise comprising a fixed jaw and a clamping jaw.
Each placing step may require a new origin located in Xdi, Ydi, and Zdi coordinates referenced to a reference point on the fixed vise jaw. And each placing step will require an indexed stop to determine the Xdi coordinate, parallels to determine the Zdi coordinate, and manipulation of the work piece. That is, the work piece is clamped using the vice clamping jaw. This involves pushing the work piece up against the fixed vise jaw to determine the Ydi coordinate and pushing the work piece up against the indexed stop to determine the Xdi coordinate. Typically the machinist assumes that the work piece remains upon and against the parallels during the clamping process to determine the Zdi coordinate.
The failure of the work piece to be properly positioned during the clamping process is referred to as a seating failure. Seating failure may also result from debris, created during the work piece cutting operations, adhering to a reference surface located on the fixed vise jaw, the indexed stop or the parallels. It would be desirable to have a CAS process to assist the machinist during work piece manipulation to identify seating failure. The prompt identification of seating failure allows the machinist to remedy the problem before continued cutting operations may ruin the work piece.
It is desirable to have a CAS process for each placing step, where the machinist may have to setup a stop or place parallels, for the computer to assist the machinist by providing instructions as to the exact coordinates so as to insure the placing step is performed accurately and correctly. Since these exact coordinates may differ from the typical digital readout values, a new display located on the machine tool table would make it much easier for the machinist to have access to this information during setup of the machine tool table. Measurement probes, such as edge finder tools, may be used to determine the exact coordinate positions of vices, indexed stops, parallels and features on the work piece. The performance of these tools is also improved by using the new display of refined positions.
Typically, a machinist uses a flexible touch probe with a dial indicator to measure small deviations between a gauge block and features on the machined part with an accuracy of ±0.0001 inches. This inspection process, sometimes using a machine referred to as a CMM (coordinate measurement machine), is performed after the part has been made, and is typically carried out in a clean room environment.
It is desirable to have a CAS process with this capability on the machine tool table so that the ±0.0001 inch accuracy can be referred to both before and during part fabrication. As a flexible touch probe with a dial indicator would be gummed up by the CNC machine cutting and coolant fluids, a new approach is needed that establishes a coordinate system of accurate points. U.S. Pat. No. 9,235,206 discloses a rigid probe to determine a single accurate position called an origin. It would be desirable to extend this approach to determine a coordinate system of accurate points.
With a rigid probe in the tool holder and the exact coordinates to insure each step is performed accurately and correctly, it would be beneficial to have a CAS process that uses the probe to assist the machinist in the setup of indexed stops. It is also desirable to have an indexed stop with probe engagement features.
Like reference numerals refer to corresponding parts throughout the several views of the drawings.